Assessing Human Vulnerability to Climate Change from an Evolutionary Perspective - Reducing Disaster: Early Warning Systems for Climate Change - page 68

Fig. 4.3 Pressure and release model: the progression of vulnerability (Adapted from Wisner et al. 2012 )
The structural perspective of vulnerability was largely formalized by the pressure
and release (PAR) model, an adapted version of which is provided in Fig. 4.3. The
PAR framework was fi rst published in Piers Blaikie, Terry Cannon, Ian Davis and
Ben Wisner's seminal topic At Risk: Natural Hazards, People's Vulnerability and
Disasters, and was re-published in 2004 and 2012. The PAR model illustrates how
underlying “root causes” of vulnerability, such as globalization, social inequalities
and colonization, place “dynamic pressures” on human systems through forces such
as political and economic marginalization, corruption, armed confl ict and ecologi-
cal degradation. Dynamic pressures, in turn, are manifest in unsafe conditions such
low-income levels, construction in dangerous locations, and poorly designed build-
ings and infrastructure. These factors are manifest in different ways in different
locations and different populations. When unsafe conditions coincide in space and
time with a hazardous event, the system, and the people inside of it, are “at risk to
disaster” (Wisner et al. 2004 ).
To further explore the concepts outlined in the PAR model, Box 4.2 juxtaposes
the impact of two events - the 2010 earthquakes that struck Haiti and Chile. These
events, of course, were not climate related; and comparisons of two extreme events
of any variety need to be considered with a degree of scepticism. However, differ-
ences between Haiti and Chile in their level of vulnerability quite clearly contrib-
uted to the wide disparity between the two countries in the number of casualties, the
economic impacts and the duration and extent of recovery.